The present invention relates to an assembly for a device for conditioning a stream of compressed air, such as an air filter, air lubricator, filter-regulator piggyback or the like, and more particularly, to an improved interlocking assembly for such a device.
In the past, conventional, industrial-quality air filter, air lubricator, and filter-regulator piggyback devices have comprised a head member, a bowl or pressure vessel and an interlocking assembly which has included an interlocking collar or locking ring used to secure the bowl or pressure vessel to the head member. The collar has had both a lip in which a shoulder on the pressure vessel is normally nested, and internal threads which are designed to be mated with external threads on the head member. An O-ring is positioned between adjacent surfaces on the shoulder and the head member in a plane transverse to the axis of the threads to seal the bowl to the head member. Another filter or lubricator device which includes those components and features is disclosed in U.S. Pat. No. 3,746,171 entitled: Filter Assembly and issued on July 17, 1973, in the name of Jack Thomsen.
While such prior interlocking assemblies have been useful, an assembly that included a threaded head member and a threaded collar was difficult to disassemble. One reason was that the head member and collar were preferably aluminum, which resulted in relatively rough threads. Another was that the O-ring, which had to be highly compressed, caused increased friction between the threads. As for the assembly disclosed in the Thomsen patent, that assembly is somewhat complex and includes a clamping collar through which the pressure vessel could be dropped, if the clamping collar and pressure vessel were not kept in registry with each other.